Active-filter tuned oscillator

An active-filter tuned oscillator is an active electronic circuit designed to produce a periodic signal. It consists of a bandpass filter and an active amplifier such as an OP-AMP or a BJT. The oscillator is commonly tuned to a specific frequency by varying the reactant of the feedback path within the circuit. An example is the Colpitts oscillator.

Properties

An oscillator is any device or system that produces a periodic output. In a tuned oscillator, the period of the output may be controlled by altering the system's resonant frequency. In the case of a tunable electronic oscillator, this is most commonly achieved by altering the circuit's capacitance.

As with all oscillators, active-filter tuned oscillators adhere to the Barkhausen stability criterion, which states that to maintain oscillation the loop gain must be unity and the phase shift must be 0 or a multiple of 2π.

External links

• Operational Transconductance Amplifiers (OTA) for synthesis of voltage-controlled active-filter tuned oscillators by Dr. William R Grise
• El 303 Analog Integrated Circuits - Active Filter Design Oscillator Design homework assignment
• What is active filter tuned oscillator? A forum thread on Edaboard.com
• Oscillators by Edgar Sanchez-Sinencio
• Active Filters and Tuned Circuits
• ECTE 313 Electronics Part II, week 4 by Daniel Franklin
• Active Filters - Characteristics, Topologies and Examples
• Oscillator Circuits
• ELG4139: Oscillator Circuits